Hazards with aluminum wiring

Buying a home with aluminum wiring? The seller will probably tell you it's perfectly fine, has never been a problem, and there's nothing to worry about. We've heard this story many times. I blogged about this topic many years ago, but it's time to revisit this topic.

Here at Structure Tech, we teach a ton of continuing education classes to real estate agents. For our Home Inspection Horrors class, we cover the known hazards with aluminum wiring and the options for repair. During a recent class, we had a real estate agent question the need for anything to be done about aluminum wiring, taking that stance that this is a perfectly good product with a bad reputation. That's not the case.

Aluminum wiring is still used today, and there's nothing inherently unsafe about it. The service wires coming into homes consists of aluminum wiring, and there are plenty of aluminum 240-volt circuits in use today. That stuff is all fine. The stuff that could be unsafe, the stuff that had problems, was a specific alloy used during a specific time, and that's what this blog post is all about.

For the rest of this post, when I refer to aluminum wiring, I'm referring to aluminum branch circuit conductors installed from approximately 1965 to 1972. "Aluminum branch circuit conductors" means wires that feed 15- and 20-amp circuits in houses. It's the wire that connects to outlets, switches, lights, and the like. That stuff had a lot of problems.

Here are a few key points about aluminum wiring, which comes from three authoritative documents at the end of this blog post:

The problem with aluminum wiring is that it expands and contracts at a high rate, which can lead to loose connections. Connections between aluminum and copper can also cause oxidation, resistance, heat, increased expansion... you get the picture. All of that can lead to a fire.

Here's an assortment of scorched aluminum wires that we've found during our home inspections. These constitute "fire hazard conditions".

We find aluminum wiring during our home inspections about once a month. I estimate that a quarter of those homes have scorched wires in the panel, but I can't comment on the rest of the wiring. Home inspectors do not pull outlets and switches out of the wall, because there's a lot that could go wrong.

If we did, however, I'm guessing we'd find a lot more scorched wiring.

There's a persistent myth that if a home was wired with aluminum 50 years ago and no fires have started, it's safe. The problem with this assumption is that when new owners move in, they will put different demands on the system. With a change in occupancy comes a change in use, and that's when problems often show up.

Past performance does not predict future performance.

Some home inspectors will recommend "monitoring" aluminum wiring for signs of problems. I take issue with this recommendation because I don't know how a homeowner is supposed to do that. Make sure the outlets don't start on fire? Pull outlets out of the wall once a month and carefully inspect the connections for overheating? Get out.

I don't know what it means to monitor aluminum wiring for problems, and I don't think most homeowners do either. Not only that, but the Consumer Product Safety Commission (CPSC) says that "failing aluminum-wired connections seldom provide easily detected warning signs."

The CPSC lists three potential repairs for homes with aluminum wiring: individual repairs with COPALUM connectors, individual repairs with AlumiConn connectors, or complete replacement of the aluminum wire. You can read about how the individual repairs would be made here: Aluminum Wiring Repairs.

Individual repairs with COPALUM connectors is not a viable option for Minnesotans. This requires the use of a specialized product that needs to be installed with a specialized tool, by a certified COPALUM Retermination Contractor. I contacted the company that provides this product and was informed that there is not a single certified contractor in Minnesota. So that's out.

It's possible to make individual repairs with AlumiConn connectors. This involves pigtailing aluminum wires to copper wires at every place the wires begin and end. The aluminum and copper wires get connected together with this specialized connector, but it's expensive.

Amazon sells a 10-pack for $45, and the price goes down when ordering in bulk quantity. Not only is the product expensive, but it's a ton of work. Every receptacle needs to be pulled and re-wired. Every switch. Every junction box. Every everything.

Not only that, but have you ever replaced an old outlet and had a difficult time getting the wires to fit back into the box properly? Just imagine at least three of these devices and twice as much wire at every box.

Besides the fact that this repair method is expensive, there's a chance that the repairs could be incomplete. Will every single junction box be found? Maybe, maybe not. Seattle home inspector Charles Buell shared a story some time ago about how he was hired to check on some repairs that were made at a home that he had previously inspected, and he found at least one junction box and one light fixture that had been missed. You can read about it here: incomplete aluminum wiring repairs.

The surest and most complete repair is to have aluminum wiring replaced. This leaves very little to chance and doesn't leave the home with a bunch of repair methods that the next semi-qualified homeowner might accidentally mess up. The obvious drawback to this is the expense involved. Of course, the expense depends on how much aluminum wiring is present and will vary greatly from house to house. This is where the electrician comes in.

If you're buying a home with aluminum wiring and you hire an electrician to inspect and/or repair the wiring, make sure they have experience with aluminum wiring repairs.

The easiest and most obvious place to find aluminum wiring is inside of the main electric panel. The pictures below show a mix of aluminum and copper wiring inside of the panels.

Just watch out for tin-coated copper wiring. This looks similar to aluminum wiring, but it wasn't used during the same period of time, wasn't increased in size like aluminum is, and typically had a cloth jacket around. This is not aluminum wiring.

Aluminum wiring can sometimes be seen by removing cover plates at outlets and switches.

Every once in a while, we'll find aluminum wires with uncapped splices. Don't ask me why. We've just found them. People do crazy things.

And finally, the least reliable method but still a good one, is to read the writing on the non-metallic sheathed cable. Specifically, look for the 10- and 12-gauge wires. Aluminum wiring will be marked as such.

If you're buying a home with aluminum wiring, have a thorough inspection of the wiring performed by an electrician and repairs made if needed. This inspection will require the inspection of at least a representative number of connections. This means pulling outlets out of the wall, pulling switches out of the wall, taking lights down to inspect the connections, pulling wires out of junction boxes, etc. If any connections aren't proper, repairs should be made.

For some more detailed discussions regarding the specific hazards with aluminum wiring, here are some excellent related documents:

Author: Reuben Saltzman, Structure Tech Home Inspections